Chapter
4
|
pH, pH/ISE and pH/LogR Measurement Modules
5.
Press the ◄ or ► key to highlight the channel setup menu that the ISE is connected with
(Channel 1, Channel 2, Channel 3 or Channel 4) and press the
f3 (Select) key.
6.
Press the ◄ or ►key to highlight Incremental Techniques and press the
f3 (Select) key.
7.
Press the
▲ or
▼ key to highlight Single Analate Addition and press the
f3 (Select) key.
8.
Press the
f3 (Clear) key as needed to delete the displayed slope value. Use the numeric
keypad to enter the ISE slope value determined in step 2 and press the
f2 (Accept) key.
9.
Enter the standard volume using the numeric keypad and press the
f2 (Accept) key.
10.
Enter the total volume (standard volume plus added ISA volume) using
the numeric keypad
and press the
f2 (Accept) key.
11.
Enter the standard concentration using the numeric keypad and press the
f2 (Accept) key.
12.
Rinse the ISE and any other electrodes in use with distilled water or rinse solution required
for that electrode. Blot the electrode dry with a lint-free tissue or shake the electrode, place
into the prepared standard and press the
f2 (Next) key.
a.
Follow all electrode rinsing and drying instructions or exceptions in the ISE user
manual. Do not wipe or rub the sensing element of the electrode.
13.
Wait for the mV value on the meter to stabilize and press the
f2 (Accept) key.
14.
Enter the analate/sample volume using the numeric keypad and press the
f2 (Accept) key.
15.
Add the analate/sample to the standard and press the
f2 (Yes) key.
16.
Wait for the mV value on the meter to stabilize and press the
f2 (Accept) key.
17.
The meter will display the calculated sample concentration and summary of the incremental
technique performed. Press the
f1 (Esc) key to proceed to the measurement mode or press
the
f2 (Next) key to perform another analysis.
Single Analate Subtraction
In single analate subtraction, the first measurement uses known standard solution containing
the type of ions that the ISE can measure and that will complex with the analate of interest in
the unknown sample. The second measurement follows the addition of the
unknown sample
that reduces the concentration of the ions in the measurement solution. The concentration of
the analate in interest in the unknown is then calculated. Concentrations are in Molarity or
Normality due to the stoichiometric nature of the subtraction.
Analate Subtraction Recommendations
Ensure the subtraction ability of the analate/sample concentration and volume added does not exceed
the concentration of the chosen standard.
A convenient standard volume is 100 mL.
The analate/sample may be added by volume only. A volume of 1 mL usually works.
The standard solution to which additions are made should be approximately 1/50
the expected sample
concentration.
54
|
Orion V
ERSA
S
TAR
Meter User Manual
Thermo
Scientific
Chapter
4
|
pH, pH/ISE and pH/LogR Measurement Modules
1.
Prepare the ion selective electrode (ISE) according to the instructions in the
electrode user
manual. Prepare all required solutions (ionic strength adjusters, standards, etc) and review
any special requirements outlined in the electrode user manual. Connect the ISE, and any
other electrodes to be used, to the module inputs on the selected channel.
2.
Determine the ISE slope as directed in the electrode user manual.
3.
In
the measurement mode, press the
channel key until the channel with the pH/ISE module
with ISE connected is shown. If needed, press the
mode key until
ISE Measurement is
shown as the measurement mode and use the
ISE Mode Menu
to set the Electrode Type.
4.
In the measurement mode, press the
setup key.
5.
Press the ◄ or ► key to highlight the channel setup menu that the ISE is connected with
(Channel 1, Channel 2, Channel 3 or Channel 4) and press the
f3 (Select) key.
6.
Press the ◄ or ►key to highlight Incremental Techniques and press the
f3 (Select) key.
7.
Press the
▲ or
▼ key to highlight Single Analate Subtraction and press the
f3 (Select)
key.
8.
Press the
f3 (Clear) key as needed to delete the displayed slope value. Use the numeric
keypad to enter the ISE slope value determined in step 2 and press the
f2 (Accept) key.
9.
Enter the standard volume using the numeric keypad and press the
f2 (Accept) key.
10.
Enter the total volume (standard volume plus added ISA volume) using the numeric keypad
and press the
f2 (Accept) key.
11.
Enter the standard concentration using the numeric keypad and press the
f2 (Accept) key.
12.
Enter the reaction ratio using the numeric keypad and press the
f2 (Accept) key.
13.
Rinse the ISE and any other electrodes in use with distilled water or rinse solution required
for that electrode. Blot the electrode dry with a lint-free tissue or shake the electrode, place
into the prepared standard and press the
f2 (Next) key.
a.
Follow all electrode rinsing and drying instructions or exceptions in the ISE user
manual. Do not wipe or rub the sensing element of the electrode.
14.
Wait for the mV value on the meter to stabilize and press the
f2 (Accept) key.
15.
Enter the analate/sample volume using the numeric keypad and press the
f2 (Accept) key.
16.
Add the analate/sample to the standard and press the
f2 (Yes) key.
17.
Wait for the mV value on the meter to stabilize and press the
f2 (Accept) key.
18.
The meter will display the calculated sample concentration and summary of the incremental
technique performed. Press the
f1 (Esc) key to proceed to the measurement mode or press
the
f2 (Next) key to perform another analysis.
Thermo Scientific
Orion V
ERSA
S
TAR
Meter User Manual
|
55